Reference [1]} also studied the presence of the graviball at dimensions \(d\)  larger than 4, in which the graviton-graviton scattering is infrared safe. The graviball still persists for \(d>4\)  and, by imposing the smoothest transition from \(d\ge 5\)  down to \(d=4\) , one could have a way to estimate the parameter \(\ln a\) . In this way, it was obtained that \(\ln a\approx 1\) , which allows to give \(s_\sigma \)  in absolute terms as \(s_\sigma =(0.22-i\,0.63)~G^{-1}\)  with an estimated uncertainty of a 20%. Reference [2]} also identifies in \(d=10\)  supergravity a prominent scalar resonance as the lightest one in graviton-graviton scattering.
